MLB: Hitting Streaks

My teen son is always coming up with good baseball questions, He asks, if a batter has a hitting streak going but then has to go on the IL, when he returns and has more hits, does that count as all part of the same hitting streak?

As I understand it, it’s games you appeared in. So sitting out a game, going on IL, or the season ending doesn’t break the streak.

That appears to be correct. A game in which the player doesn’t make an appearance doesn’t break the streak. As per Wikipedia (bolding mine):